1. Field of the Invention
The present invention relates to a power-saving method applied to a network system and a related apparatus, and more particularly, to a method and a related apparatus capable of entering and leaving a low power state in the PHY layer to save power.
2. Description of the Prior Art
In a high-speed network system, such as 1 Gbase-T/10 Gbase-T Ethernet system, the power consumption of the network system increases correspondingly if its circuits operate frequently. Hence, how to save the power consumption of the network system becomes an important topic of the field.
At present, the method of work is using lower frequency to transmit link pulses when the physical layer of the network system is in the non-link state to achieve the goal of saving power. If the network system is in the link state, the power-saving mechanism focused on the physical layer can save power only by lowering speed or by lowering the transmitting capacity of the transmitter or the receiving capacity of the receiver. However, when the network system is in the link state, the power-saving effect of such mechanism is not good enough, due to all of the circuits of the transmitter and the receiver being still in power-on state.
The traditional network system must keep sending out a fixed idle pattern to maintain a connection when lying in the link state, even if there is no packet to be transmitted and it is in the idle state. In order to let the remote network device identify the idle pattern, this idle pattern must conform to Ethernet standard idle signal defined by IEEE standard. At this time, the power consumption of the network system is slightly lower than the power consumption in the normal state (i.e., transmitting the packets), which is actually not cost-effective. In addition, another method for saving power by changing the transmission characteristics of the idle pattern has already been disclosed in the prior art, which can be referred to U.S. Published Application No. 2008/0225841.